For impact energy absorption (Energy Absorption: EA) in the event of a collision on a side (a lateral collision), an EA material made of rigid urethane is mounted to a door trim of an automobile. As a method for mounting the EA material made of rigid urethane to the door trim, Japanese Unexamined Patent Application Publication No. 2001-322507 describes the structure illustrated in FIGS. 7, 8a, and 8b. FIG. 7 is a cross-sectional view illustrating a mounting structure for an EA material described in FIG. 7 of the above publication. FIG. 8a is a perspective view of a cap (a cylindrical member) 20 used in the structure, and FIG. 8b is a cross-sectional perspective view of the cylindrical member 20.
The cap 20 integrally includes a cylindrical portion 21 and a flanged portion 22. The cylindrical portion 21 is provided with a pawl 23 directed inwardly from the leading end of the cylindrical portion 21. A rod 26 projects from a trim 31, and a concavity 27 is formed around the outer circumferential surface of the rod 26. The pawl 23 engages with the concavity 27.
The cylindrical portion 21 is formed with slits 24 extending from the leading end thereof in the direction parallel to the axis center line of the cylindrical portion 21. The cylindrical portion 21 is elastically deformable in the diameter expanding direction thereof.
To mount an EA material 33 to the trim 31, the EA material 33 is aligned with the surface of the trim 31 such that the rod 26 is inserted into a mounting hole 34 of the EA material 33. Then, the cap 20 is fitted and pressed onto the rod 26 to engage the pawl 23 with the concavity 27. Thereby, the flanged portion 22 presses the peripheral region around the mounting hole 34 of the EA material 33.
The cylindrical portion 21 is formed in a taper shape tapered toward the leading end thereof, and thus can be easily inserted into the mounting hole 34. In a state in which the cap 20 is fitted to the rod 26, the outer circumferential surface of the cylindrical portion 21 is in close contact with the inner circumferential surface of the mounting hole 34.
In the above conventional mounting structure for an EA material, the cap 20 and the EA material 33 are separate from each other. The mounting of the EA material to the trim 31, therefore, requires two operation processes, i.e., an operation of applying the EA material to the trim 31, and a subsequent operation of fitting the cap 20 onto the rod 26. As a result, the operations become troublesome.
When a passenger hits the EA material 33 and the EA material 33 is crushed and deformed, the cap 20 resists the crushing deformation, and the EA characteristic is decreased for that.
Since the pawl 23 can move in the concavity 27, the EA material 33 may move in the horizontal and vertical directions in FIG. 7. This may cause abnormal noise.